Typically, in an image forming apparatus, toner is transferred onto a sheet and is then heated and fixed. Conveying rollers convey the sheet on which the toner is heated and fixed to an automatic duplexing device, a paper discharge unit, a finisher device, or the like. The toner on the sheet immediately after being heated and fixed has a high temperature and thus is not immediately cooled. Therefore, the conveying rollers convey the sheet in a high temperature state. In general, the conveying rollers include a plurality of rubber rollers that has a width smaller than that of a sheet on the axis of the conveying rollers in terms of reducing costs.
The low temperature rubber rollers, through contact with the sheet, remove heat from the toner on the sheet while conveying the high temperature sheet. A temperature difference occurs in the toner on the sheet between the portion of the sheet that comes into contact with the rubber rollers and the portion thereof that does not come into contact with the rubber rollers. That is, the cooling of the toner on the sheet becomes different. When the toner on the sheet cools, a gloss difference occurs between the portion of the sheet that comes into contact with the rubber rollers and the portion thereof that does not come into contact with the rubber rollers. As a result, unevenness in gloss occurs on the surface of the sheet. Especially, similarly to a color photograph, when a toner image is transferred over the entire surface of a sheet such as a thick sheet, a coated sheet having glossy coating, or a water-proof sheet, stripe-like unevenness in gloss becomes noticeable on the surface of the sheet.